Cognitive components in risk perception: Natural versus manmade risks

In a questionnaire study 106 Norwegian students rated natural and manmade hazards according to risk magnitude and public versus private responsibility for risk management. Another group of 50 subjects judged 36 natural hazards on nine risk dimensions used in previous psychometric studies of ‘manmade risks’. When ratings on nine risk characteristics for natural hazards were factor analyzed a three-dimensional solution was found, with one active/passive dimension, one potency dimension, and one novelty dimension. This contrasts with the two-dimensional solution found for manmade hazards. Responsibility for risk management was found to be related to the type of risk in focus, and different risk characteristics seem to play different roles for manmade and natural hazards.     

Evaluating performance in continuous experiments with feedback to subjects

Consider an experiment in which a subject guesses repeatedly at a randomly chosen target on a continuum. To guarantee a positive probability of success, the continuum is partitioned into a finite but large number of segments. The subject is given directional feedback. General guessing strategies are characterized, and an optimal strategy is identified. The hypothesis that the subject's performance can be explained by chance alone is of interest in such experiments. A test is developed based on comparing the subject's performance to expected performance using the optimal strategy. A skill-scoring procedure is developed for assessing a subject's performance in light of the strategy used, and a test based on skill-scoring is advanced.Research by the first author is supported in part by the Air Force Office of Scientific Research under grant AFOSR 77-3180.The authors wish to thank the referees for remarks that led to improvements in both content and clarity.     

Nonmetric maximum likelihood multidimensional scaling from directional rankings of similarities

A maximum likelihood estimation procedure is developed for multidimensional scaling when (dis)similarity measures are taken by ranking procedures such as the method of conditional rank orders or the method of triadic combinations. The central feature of these procedures may be termed directionality of ranking processes. That is, rank orderings are performed in a prescribed order by successive first choices. Those data have conventionally been analyzed by Shepard-Kruskal type of nonmetric multidimensional scaling procedures. We propose, as a more appropriate alternative, a maximum likelihood method specifically designed for this type of data. A broader perspective on the present approach is given, which encompasses a wide variety of experimental methods for collecting dissimilarity data including pair comparison methods (such as the method of tetrads) and the pick-M method of similarities. An example is given to illustrate various advantages of nonmetric maximum likelihood multidimensional scaling as a statistical method. At the moment the approach is limited to the case of one-mode two-way proximity data, but could be extended in a relatively straightforward way to two-mode two-way, two-mode three-way or even three-mode three-way data, under the assumption of such models as INDSCAL or the two or three-way unfolding models.The first author's work was supported partly by the Natural Sciences and Engineering Research Council of Canada, grant number A6394. Portions of this research were done while the first author was at Bell Laboratories. MAXSCAL-4.1, a program to perform the computations described in this paper can be obtained by writing to: Computing Information Service, Attention: Ms. Carole Scheiderman, Bell Laboratories, 600 Mountain Ave., Murray Hill, N.J. 07974. Thanks are due to Yukio Inukai, who generously let us use his stimuli in our experiment, and to Jim Ramsay for his helpful comments on an earlier draft of this paper. Confidence regions in Figures 2 and 3 were drawn by the program written by Jim Ramsay. We are also indebted to anonymous reviewers for their suggestions.     

Auditorily elicited EEG desynchronization and synchronization: A review of Christina M. Krause's doctoral thesis

The present paper reviews the doctoral dissertation of Christina M. Krause, in which auditorily elicited EEG desynchronization (ERD) and synchronization (ERS) was studied in five experiments. These experiments which were conducted by Krause and co-workers are the first in which the ERD-method was systematically applied to the analysis of the perception and processing of complex auditory stimuli. The main conclusion is that listening to sounds elicits ERS, whereas cognitive and/or memory processes elicit ERD.     

Postural stabilization for the control of touching

We attempted to distinguish between task-related (supra-postural) and perceptual influences on postural motions. Two groups of participants had to make very light tactile contact with an adjacent pliable surface while standing with their eyes closed. In the absence of vision, such light touching with a finger is known to reduce sway. For one group, tactile contact with the surface was merely the result of extending the right forearm. For the other group, variability in the point of tactile contact had to be kept to a minimum. Touching reduced postural sway relative to non-touching only for participants in the latter group. The present results, in combination with others addressing similar task differences, question the assumption that information detected haptically and/or visually is used solely to reduce postural fluctuations. It seems that postural fluctuations are modulated to facilitate performance of tasks over and above the task of standing upright and still.     

在不同注意定向条件下是否出现返回抑制的知觉优先

返回控制中的知觉优先是指相对于非线索化位置,线索化位置的刺激被优先知觉到的现象。研究采用时序判断方法对不同注意定向下返回抑制的知觉优先现象进行了两个实验。实验１采用连续线索化的安排,发现当注意从线索化位置移开后知觉优先仍然存在;实验２采用同时呈现双线索的安排发现知觉优先也存在。     

时距知觉的心理学研究

本文回顾了近五十年来时距知觉的实验研究,对不同的理论模型、实验范式、实验方法以及主要时距判断规律作了较全面的评述,并进一步探讨了时距知觉研究未来的发展。     

Irrational action and irrational belief

Many philosophers agree with Socrates that it is not possible to perform an akratic action consciously and freely. They take this view because they assimilate the internal irrationality of such a performance to the internal irrationality of drawing a theoretical conclusion which contadicts one's premisses. This article develops some arguments against that assimilation. The extreme cost of theoretical self-contradiction is forming the belief both that something is so and that it is not so. This is impossible for anyone who understands what he is doing, and the impossibility can be explained: nothing could conceivably make such a conjunction of beliefs true. But the conjunction of a value-judgement judgment and an action that gets against it is different. Although it too is internally irrational, there is no property like truth which the value-judgement and his action ought both to possess, but cannot both possess. This article proposes a different model for akratic action, which might serve as a basis for disagreement with Socrates' view of it.